Porto claims to be the workhorse of Portugal. It's a city worth seeing - though you may feel a tendency towards a crick in the neck because your view is always drawn upwards to the tops of the high buildings.
It's largely the steep sided Douro river that conveys Porto's special appeal - particularly the splendid two level bridge. Get a bus map and find a route crossing at the upper level - then walk down and get one back - or walk - at the lower level. Don't try the reverse unless you have severe masochistic tendencies.
Even if you are in a car or coach, make a point of seeing Sao Bento Station. The tiles in the foyer are truly something else. Also see at least one of the old port wine lodges on the other side of hte Douro and the old boats once used for its transportation. [edit text][editors]